The perimeter of the rectangle is 22 cm, and one of its sides is 7 cm, find the second side of the rectangle.

It is known that the perimeter of a rectangle is 22 cm, and one of its sides is 7 cm. Let’s define the second side of the rectangle.
The perimeter is the sum of the lengths of all sides of the rectangle. Hence, we get the following solution.
P = (a + b) × 2.
22 = (a + 7) × 2.
a + 7 = 22 ÷ 2.
a + 7 = 11.
a = 11 – 7 = 4.
This means that the second side of the rectangular is 4 cm.
Answer: the second side of the rectangle is 4 cm.